JP2014002995A - Led surface light-emitting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a surface light-emitting device using an LED light source capable of establishing compatibility between suppression of illuminance unevenness on a light-emitting surface and the slimming-down of a device body.SOLUTION: A light diffusion member comprising oblique lattice-shaped continuous uneven surfaces facing each other along an optical axis of an LED light source is arranged. Thus, a surface light-emitting device with a small body thickness makes uniform irradiation light obtained on a surface of a translucent display panel by making an outgoing beam from the LED light source evenly diffused and reflected by the uneven surface of the light diffusion member.

Description

  The present invention is a light-emitting device that uses an LED light source inside a box, has a low power consumption, a thin box, and a light-emitting surface with little uneven illuminance, a light-emitting signboard, an internally illuminated sign, a display device, and a lighting fixture The present invention relates to an LED surface light emitting device that is optimal for surface light emission.

  A light source is arranged inside the box-like body, and a light-emitting signboard such as a light-emitting signboard having one surface of the box-like body as a display surface, or a light-emitting signboard having a light source inside the wall surface with a part of the wall surface as a display surface As the surface light emitting device, a fluorescent light source is widely used. However, in a straight tube fluorescent lamp, the lifetime of the light source is generally about 12000 hours. However, the lifetime of each light source varies, and the lamp needs to be replaced before reaching the lifetime. For this reason, there was a problem that running cost including lamp replacement was high.

  Therefore, recently, surface light-emitting devices such as light-emitting signs using LEDs as light sources have been widely used. In this case, since the lifetime of the LED light source is generally set to 40000 hours or more, the lifetime is approximately three times that of the straight tube fluorescent lamp, and the power consumption is also approximately ½, so that the running cost can be reduced.

  For example, as shown in Patent Document 1, a plurality of LEDs are arranged opposite to each other on the side wall portion inside the box-shaped body, and a transparent light diffusion surface plate is provided at the front opening of the box-shaped body. Even when using a light source with strong directivity of light, such as an LED, by installing a reflecting plate that forms a mountain-shaped convex part that protrudes toward the front opening at the bottom of the box-shaped body By changing the direction of light and coming out on the surface of the light diffusing surface plate, a technology for realizing a surface light emitting device such as a light emitting signboard without light unevenness has been made.

  JP 2006-202729 A   Japanese Utility Model Publication No. 6-15006   JP-A-7-72815

  Recently, there has been a strong demand for space saving and light weight for display devices such as signboards, and for this reason, it is required to reduce the thickness of the box-like body while ensuring uniform illumination unevenness on the display surface. . In a device that radiates light from a conventional light source to a reflecting plate that forms a mountain-shaped convex portion and reflects and displays the reflected light on the display plate, the size of the box-shaped body is limited by the shape of the reflecting plate. There was a limit to achieving both uniform illumination unevenness and the thickness of the box-shaped body.

  Therefore, the present invention has been made in view of the problems of the prior art, and it is an object of the present invention to provide a display device such as a signboard having a thin box-like body without uneven illuminance on the display surface.

  As a result of repeated studies to solve the above problems, it has been found that a display device can be obtained in which the thickness of the box-shaped body is thin without uneven illumination on the display surface in the relationship between the optical axis position of the LED light source and the light diffusing member. It was. That is, in the display device according to the first aspect of the present invention, a light diffusing member having a concavo-convex surface is disposed on a surface facing the transflective display panel, and the side wall portion constituting the box-like body is substantially parallel to the light diffusing member. In the display device provided with the LED light source that distributes the optical axis, the uneven surface of the light diffusing member is a continuous uneven surface in an oblique lattice shape facing along the optical axis of the LED light source. LED surface light emitting device. A display device according to a second aspect of the present invention is the LED surface light emitting device according to the first aspect of the present invention, characterized in that the cross-sectional shape of the convex portion tip of the oblique lattice-like continuous concave-convex surface is configured by a curve. The display device according to a third invention is the display device according to the first and second inventions, wherein the relationship between the aspect ratio h and the aspect ratio B of the convex cross section of the oblique lattice-like uneven surface is B / 5 ≦ h ≦ B / 2 is an LED surface light emitting device. A display device according to a fourth invention is the display device according to any of the first, second and third inventions, wherein the light diffusing surface of the light diffusing member provided with the oblique lattice-shaped uneven surface is a diffuse reflecting surface having a reflectance of 80% or more. It is the LED surface emitting device characterized by having performed. A display device according to a fifth invention is the display device according to the first, second, third, or fourth invention, wherein the LED light sources are arranged in at least two opposite directions of the side wall member constituting the box-shaped body. is there. A display device according to a sixth invention is the display device according to the first, second, third, fourth, or fifth invention, wherein the emitted light in the vertical direction from the LED light source is within 16 ° outward with respect to the optical axis. The LED surface light emitting device is characterized in that the emitted light in the horizontal direction is 20 ° or more outward with respect to the optical axis. A display device according to a seventh invention is the display device according to the first, second, third, fourth, fifth, or sixth invention, wherein the inner wall surface of the box-shaped body has a reflective surface having a reflectance of 85% or more. It is the LED surface emitting device characterized by having performed.

  The LED surface light emitting device according to the present invention can illuminate the display surface by diffusing and reflecting the light from the light source by a light diffusing member having an uneven surface, even when using a light source with strong directivity of light such as an LED. There is no unevenness, it is possible to obtain uniform illumination on the display surface, and since a light diffusion member with a small thickness is used, the overall thickness of the device can be reduced. Can be achieved.

  It is sectional drawing which shows the Example of LED surface light-emitting device.   It is an enlarged view of the light source part cross section of a LED surface light-emitting device.   It is a front view which shows the diffusion surface convex part shape and optical axis of a light-diffusion member.   It is sectional drawing which shows the diffusion surface convex part shape of a light-diffusion member.   It is an exploded view which shows the structure part of the whole LED surface emitting device.

  The display device of the present invention includes a box-shaped body provided with a transflective display panel on the front surface, and at least two-direction LED light source modules disposed in parallel to the side wall portion of the box-shaped body, It consists of the light-diffusion member provided with the uneven surface laid in the bottom part of this box-shaped body.

  In the LED light source module according to the present invention, the LED disposed in the LED light source module and the diffusing surface of the light diffusing member having the concavo-convex surface in at least two opposing directions of the side wall of the box-shaped body. It arrange | positions so that the optical axis of a light source may become parallel. For example, when the bottom of the box-shaped body is rectangular, the two-way LED light source module may be installed in parallel with the side wall on the short side or in parallel with the side wall on the long side. . Further, the LED light source module may be installed in parallel to all the four side walls.

  The light diffusing member having the uneven surface is laid on the bottom of the box-like body so as to be substantially parallel to the optical axis from the LED light source in the LED module provided on the side wall of the box-like body. By arranging the optical axis position of the LED light source at the position where the emitted light enters the light diffusing plate having an uneven surface, the illuminance on the display surface of the transflective display portion can be made uniform.

  In the LED light source module, one or a plurality of LED light sources are arranged at a substantially constant interval in the longitudinal direction of the LED light source module.

  The LED light source module is mainly composed of a housing part that accommodates the entire components of the LED light source, an LED light source housed inside the housing part, a lens member, and a circuit board of the LED light source. One or a plurality of (for example, three) LED light sources are mounted (arranged) on the circuit board, and the LED light sources and the like are positioned by the housing portion. A lens member is disposed on the light emitting part from the LED light source of the housing part, and the light emitting angle of the light from the LED light source is determined by the lens member, and the vertical emitting angle is outward with respect to the optical axis. Within 10 °, the horizontal emission angle is set to be 20 ° or more outward with respect to the optical axis, and the housing part that houses all the components of the light source is made of a heat conductive material (for example, aluminum) It makes it easy to dissipate heat from the LED light source and the circuit board.

  The light diffusing member in the present invention is laid with the light diffusing member in close contact with the bottom of the box-like body parallel to the surface of the translucent display panel disposed on the front surface of the box-like body. The light diffusing member is composed of a light diffusing surface having a concavo-convex shape in a direction facing the display panel. For example, the concavo-convex shape has a continuous convex portion in an oblique lattice shape inclined by 45 ° with respect to the optical axis of the LED light source. And the cross section of a convex part is comprised by a curve. The inclination angle of the oblique lattice-shaped convex portion with respect to the optical axis may be in the range of 30 to 60 °. The uneven shape of the light diffusing member may be a shape in which arc-shaped convex portions are continuously combined in a substantially diagonal lattice shape.

  The light diffusing member is formed by molding a thermoplastic resin such as polycarbonate, acrylic resin, polyethylene, polypropylene, polyvinyl chloride, acrylonitrile butadiene styrene resin, polyamide, polyacetal, etc. to form a diffusing surface. Uses an opaque white sheet formed by vacuum molding or an injection molded white panel. The light diffusing member may be a soft foam such as foamed polyethylene or a foam such as foamed polystyrene, and the light diffusing surface may be formed on a metal plate such as an aluminum plate or an iron plate.

  In the present invention, the material of the translucent display panel disposed in the front opening of the box-like body is an acrylic resin milky white plate with a plate thickness of preferably 2 mm to 5 mm, and a total light transmittance of 20% to 60%. The total light reflectance is preferably 40% or more and 80% or less.

  Examples of the LED surface light emitting device 10 of the present invention will be described below. FIG. 1 is a cross-sectional view showing an embodiment of an LED surface light emitting device 10 according to the present invention, and FIG. 2 is an enlarged view of a light source unit of FIG. FIG. 3 is a front view showing an embodiment of the diffusing surface convex portion 41 and the optical axis 301 of the light diffusing member 40. FIG. 4 is a cross-sectional view showing the shape of the diffusing surface convex portion 41. FIG. 5 is an exploded view showing components of the entire LED surface light emitting device 10.

  The inner dimensions of the box-shaped body 11 shown in FIG. 1 are 405 mm in length, 690 mm in width, and 33 mm in height, and the semi-transparent display panel 20 is detachably attached to the upper front opening of the box-shaped upper part 12. The light diffusing surface of the light diffusing member 40 was laid on the bottom surface of the main body 11 so as to be in close contact with the bottom surface of the box-shaped main body 11 so as to face the translucent display panel 20. Two LED light source modules 30 are attached to the box-like body wall portions 11 a on the left and right sides of the box-shaped body 11 so as to face each other, and the vertically emitted light from the lens member 32 of the LED light source 31 in the LED light source module 30. When the distance to the optical axis 301 is Lb = 10 mm, the distance from the optical axis 301 to the vertex of the diffusing surface convex portion 41 of the light diffusing member 40 is set to La = 15 to 16 mm in the embodiment.

  The translucent display panel 20 of FIG. 1 uses a 3 mm thick milky white acrylic plate (trade name acrylite, manufactured by Mitsubishi Rayon Co., Ltd.) having a total light transmittance of 58% and a total light reflectance of 40%.

  The light diffusing member 40 shown in FIGS. 1 and 3 is a polycarbonate white sheet having a thickness of 0.5 mm and uses a total light reflectance of 95 to 98%, and the diffusing surface convex portion 41 is formed with the translucent display panel 20 by vacuum molding. The diagonal diffusion pattern convex portions 41 inclined at 45 ° with respect to the optical axis 301 of the LED light source 31 in the opposite direction are arranged at intervals of P = 14 mm in the diagonal direction, and the convex portions shown in FIG. The cross-sectional shape was such that the bottom width was set to B = 5 mm and the height h = 1.5 mm, and the tip of the convex portion was constituted by a curve.

  The LED light source module 30 shown in FIGS. 1 and 2 includes a housing 35 that houses all the components of the light source and three LED light sources 31 that are housed inside the housing 35. The optical axis 301 of the LED light source 31 is arranged on the line, and the optical axis of the LED light source 31 is arranged at positions at equal intervals on the left and right with respect to the center in the longitudinal direction. The LED light source 31 includes a lens member 32, a cover 33, and a circuit board 34. Three LED light sources 31 are mounted on the circuit board 34, and the mounting position of the LED light source 31 is determined by the cover 33. . A lens member 32 is disposed on the light emitting portion of the LED light source 31, and the lens member 32 determines the light emitting angle of the LED light source 31, and the vertical emitting angle is 8 ° outward with respect to the optical axis. The horizontal emission angle was set to 20 to 30 ° outward with respect to the optical axis. The housing 35 for housing all the components of the light source was constructed by extrusion molding of aluminum.

The display surface of the semi-transmissive display panel 20 was measured with an illuminance meter (custom model name: LX-1000). In the horizontal measurement position, the position 45 mm from the inside of the box-shaped body 11 is set to (1), and intervals of (1), (2), (3), (4), (5), and (6) are measured. Was 120 mm. In the vertical direction, the position 52 mm from the inner side of the box-shaped body 11 was set to A, the intervals of A, B, C, and D were set to 100 mm, and the surface illuminance at 24 points intersecting the horizontal measurement position was measured. Table 1 shows the average values of the vertical measurement positions A, B, C and D at the horizontal measurement positions (1) to (6) at 24 measurement points. It confirmed that the surface illumination nonuniformity of the LED surface light-emitting device of this invention decreased with respect to a comparative example.

(Comparative example)
The light diffusing member 40 of the example was removed, and a flat white polycarbonate sheet having a thickness of 0.5 mm was laid with a total light reflectance of 95 to 98% in close contact with the bottom surface of the box body 11. The light diffusing member 40 was removed and the white sheet was laid, and the configuration was the same as in the example. As a result of measuring the surface illuminance, a decrease in the surface illuminance near the center of the semi-transmissive display panel 20 was confirmed.

  A light diffusing member is disposed on the surface facing the color liquid crystal panel, an LED light source is provided on the inner side wall portion constituting the box-shaped body of the entire color liquid crystal display, and the emitted light from the LED light source is transmitted through the light diffusing member through the light diffusing member. By diffusing and reflecting to the color liquid crystal panel, it can also be used as a backlight for a color liquid crystal display.

DESCRIPTION OF SYMBOLS 10 LED surface light-emitting device 11 Box-shaped body main body 11a Box-shaped body side wall part 12 Box-shaped body upper part 20 Semi-transmissive display panel 30 LED light source module 31 LED light source 32 Lens member 33 Cover 34 Circuit board 35 Housing 40 Light diffusion member 41 Diffusion Surface convex part 301 Optical axis

Claims (7)

  A display provided with an LED light source in which a light diffusing member having an uneven surface is arranged on a surface facing a transflective display panel, and an optical axis is distributed substantially in parallel with the light diffusing member on a side wall portion constituting a box-shaped body In the apparatus, the uneven surface of the light diffusing member is a continuous uneven surface in an oblique grid shape facing along the optical axis of the LED light source.   2. The LED surface light emitting device according to claim 1, wherein a cross-sectional shape of a tip of the convex portion of the uneven surface having the oblique lattice shape is a curve.   3. The LED surface light emitting device according to claim 1, wherein the relationship between the aspect ratio of the convex cross-sectional shape of the convex-concave surface of the oblique lattice-like surface is B / 5 ≦ h ≦ B / 2. .   4. The LED surface light emitting device according to claim 1, wherein the light diffusing surface of the light diffusing member provided with the oblique lattice-like uneven surface is a diffuse reflecting surface having a reflectance of 80% or more.   5. The LED surface light emitting device according to claim 1, wherein the LED light source is disposed in at least two opposite directions of a side wall member constituting the box-shaped body.   The vertical emitted light from the LED light source is within 16 ° outward with respect to the optical axis, and the horizontal emitted light is 20 ° or more outward with respect to the optical axis. The LED surface light-emitting device of claim | item 1, 2, 3, 4, 5.   7. The LED surface light emitting device according to claim 1, wherein the inner wall surface of the box-like body is a reflecting surface having a reflectance of 85% or more.

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